Elastomeric articles made from natural or synthetic rubber are used in many different applications including being used as surgeons gloves, examining gloves, prophylactics, catheters, balloons, tubing, and the like. Elastomeric materials have been useful in the production of such articles because of their physical properties. For example, these materials exhibit very elastic properties. The materials not only can be stretched many times their length, but are also capable of substantially returning to their original shape when released.
Traditionally, elastomeric articles have been manufactured through the use of a mold or former in the shape of the final article to be produced. For example, when manufacturing a glove, a hand-shaped mold or former is first dipped in a coagulant slurry containing calcium nitrate and calcium carbonate. After the slurry has dried on the former, the former is dipped in an elastomeric material such as a natural or synthetic latex such that a coating is coagulated on the former. The formed elastomeric article is then cured and cooled and stripped from the mold which turns the glove right side out.
Elastomeric articles are typically tacky to the touch when initially manufactured. The tackiness increases the difficulty in handling the glove during manufacture, packaging, and final use. Difficulties encountered include problems in stripping the product from the mold during manufacture, products sticking to each other during packaging, and, when gloves are produced, problems with donning the gloves and gripping and feeling articles when wearing the gloves. As a result, elastomeric articles are usually further processed to reduce their tackiness. Historically, the most common process for reducing tackiness has been the application of a powder such as cornstarch to the surfaces of the glove. While the use of a powder is acceptable for some applications, powders may not be used in certain applications, such as surgical or other clean room type applications.
As a result, powder free processing techniques have been developed. For example halogenation, such as chlorination, and other chemical surface treatments have been developed in order to eliminate powders on the product. However, these powder free techniques tend to not only be expensive, but may also reduce the shelf life of the treated elastomeric article. Other methods of forming a powder-free glove, such as the methods disclosed in U.S. Pat. No. 5,993,923 to Lee, which is incorporated herein by reference, can include forming a powder free polymeric coating on the glove. These coatings can be relatively thick, however, from about 10 to about 25 microns on one or both surfaces of the glove. Such thick coatings can interfere with tactile sensitivity necessary when wearing the gloves, as well as interfere with the desired characteristics, such as the stretching and modulus characteristics, of the primary matrix forming the glove body.
Another problem experienced with elastomeric articles in the past is that the outer surfaces may become slippery when they are wet, and the wearer may find it more difficult to grasp objects in the gloved hand without losing the grip. This problem is particularly troublesome for gloves treated by powder-free processing techniques, because the very processing which reduces tackiness on the surface of the glove can also promote excessive loss of gripping ability.
Thus, a need exists for a powder free elastomeric article which may be easily stripped from the forming mold and has good gripping and tactile characteristics, while retaining the desired characteristics of the primary matrix forming the body of the article.